Circular



Feb. 15, 1944. J P PUTNAM CIRCULAR MOTION MECHANISM Filed Nov. '7, 1941 4 Sheets-Sheet l- INVEN+EIRI Feb. 15, 1944.

J. P. PUTNAM CIRCULAR MOTION MECHANISM Filed Nov. '7, 1941 4 Sheets-Sheet 2 Feb. 15, 1944. J. P. PUTNAM CIRCULAR MOTiON MECHANISM- 4 Sheets-Sheet 3 Filed Nov. 7, 1941 Feb. 15, 1944. .1. P. PUTNAM CIRCULAR MOTION MECHANISM Filed Nov. 7, 1941 4 Sheets-Sheet 4 I NVENIEJ R:

M WM

Patented Feb. 15, 1944 UNITED STATES PATENT OFFICE CIRCULAR MOTION MECHANISM Application November 7, 1941, Serial No. 418,209

10 Claims.

This invention relates to circular motion mechanisms and more particularly to circularly extensible and contractible, divisional structures.

Circularly extensible and contractible, divisional structures have been used heretofore. They have, for instance, been associated with extensible and contractible, flexible scales for the intended purpose of varying the graduations of the scale in constant ratio with the extension and contraction of these structures. An eXample of such an application of a circularly extensible and contractible, divisional structure is given in a prior application Serial No. 393,517, filed May 15, 1941. These prior structures have, however, considerable play or lost motion in the several divisions thereof, with the result that the latter do not expand or contract as uniformly as is required, for instance, of the graduations of a scale for accurate, instead of only approximate, readings.

The present invention has for its object the provision of a circularly extensible and contractible, divisional structure in which the play in the several divisions is for all intents and purposes eliminated so that the divisions expand or contract most uniformly. V

The invention will best be understood from the following description of an illustrative embodiment thereof shown in the accompanying drawings in which:

Fig. l diagrammatically illustrates a straight line mechanism which forms the basis for the present invention. I

Figs. 2 and 3 are diagrammatic views illustrative of the present invention.

Fig. 4 is a fragmentary plan view of mecha-. nism embodying the invention.

Fig. 5 is an enlarged plan view, partly in section, of an instrument in which the present invention finds, by way of an example, practical application.

Fig. 6 is a similar view of the instrument with certain parts thereof removed for better illustration of the applied invention.

Fig. '7 is a side elevation, partly in section, of the instrument, the section being taken substantially on the line 1-1 of Fig. 5.

Fig. 8 is a fragmentary section taken substantially on the line 88 of Fig. 6.

Referring to the drawings and particularly to Fig. 1 thereof, there is shown a straight line mechanism which forms the basis for the present invention. This mechanism comprises two links 8 and 9 and a rocker Ill. The links 8 and 9, which are of equal length, are rotatable about fixed pivots d and 0, respectively, and are pivotally connected with the rocker l0 at a and b, respectively. The point p of the rocker is spaced from the pivots a and b at an equi-distance which is equal to the length of either link 8 or 9. The length of the side of the rocker opposite the point p is immaterial. With these conditions prevailing, the point p of the rocker ID will move in an approximately straightdine passing through the fixed pivots c and d when the mechanism 8, 9, II] is rocked in either direction about the fixed pivots d, c. The limits of the approximate straight line motion of the point p are adjacent the fixed pivots c and d, respectively (see dotted and dot-and-dash line positions of mechanism 8, 9, Ill). The longer the links 8, 9 and the sides of the rocker lll which meet at the point p are in comparison to the distance between the fixed pivots d and c, the more closely will the point p travel in a straight line. The straight line mechanism is applied to the present invention in the manner illustrated in Figs. 2 and 3. In Fig. 2, the links 8 of two straight line mechanisms of identical dimensions are formed by portions of two arms I la and llb which are turn'able about fixed pivots d, respectively, While the links 9 are rotatable about fixed pivots c, respectively. On turning either arm lla or llb about its fixed pivot 11, the point p of the corresponding mechanism will travel on an approximately straight line. If the parts of the two identical straight line mechanisms assume the same relative disposition, as shown in full lines in Fig. 2, it is evident that equal angular displacement of the arms Ila and llb from their full line position (Fig. 2) into the dotted line position, for instance, will result in identical displacement of the mechanisms. Conversely, equal displacement of the mechanisms from the identical full line positions into the dotted line positions in Fig. 2, for instance, will result in equal angular displacement of the arms Ho. and llb. These functions of identical straight line mechanisms are utilized in the construction shown in Fig. 3. Here, three arms lla, llb and He are rotatable about a common axis d, and the arms Ho and llb are associated with the same identical straight line mechanisms shown in Fig. 2. "The ,third arm He has a common pivotal connection c' with the links 9, 9 of the straight line, mechanisms. The rocker I0 is provided with a pin l2 whose center is the same as the point p of the mechanism which includes the arm lla in Fig.

2, while the rocker lll" is provided with a slot l3 in which the pin E2 is received. The slot l3 extends transversely to a straight line passing through the pivots c and (2. With these conditions prevailing, and with the arm lie, for instance, held stationary, a turning of either arm Ila or III) in either direction through a certain angle will result in a turning of the other free arm in the opposite direction through the same angle. This is due to the connection l2, l3 between the rockers Ill and ill" of the straight line mechanisms which compels the latter to be equally displaced when either one is displaced. By the same token, the arm lla, for instance, may be held stationary and arm He turned in either direction through a certain angle, in which case the arm ll b will be turned in the same direction through twice said angle. Conversely, with the arm lla held stationary, the arm llb may be turned in either direction through a certain angle, in which case the arm He is turned in the same direction through one-half said angle. Also, the arm Ila, for instance, may be dispensed with and the rocker l9 rotatably mounted on a fixed pivot a. In that case, either one of the arms llb or ll may be turned, and such turning will have the same result on the other arm as described in the two preceding examples. Since both, the pin l2 and the slot l3, travel in a common, approximately straight path which extends through the pivots d and c and hence, radially of the common turning axis of the arms Ila-c, it is evident that whatever relative motiton there is between the pin and slot transversely to their' common radial path is very small. Of course, when the pivots a, a and 0' lie in the longitudinal axes of the arms Ila, llb and lie, respectively, as they do in Fig. 3, the arms lla.--c are equi-angularly spaced in any angular relative disposition.

The construction shown in Fi 3 has for all intents and purposes no play between the vari ous parts thereof. All the connections between the parts, except the pin and slot connection l2, l3, are non-floating pivot connections in which all play can be eliminated without difiiculty. As mentioned above, the pin l2 and slot l3'move together in a near linear path and have very 'little relative movement transversely thereto, so

that an accurate fit of the pin without play'in the slot in any position on said linear path is not difficult to attain. Hence, the pin and slot connection l2, l3 has for all intents and purposes no more play than a non-floating pivot connection. In the absence of any appreciable play between the parts of this construction, the reaction of the slightest turning movement of one of the arms llac upon the other arms is instantaneous and not delayed by any lost motion.

Fig. 4 illustrates a preferred coordination of the parts where more than three radial arms are angularly extensible and contractible. Since the coordination of the arts may be the same for any number of radial arms over three, there are shown, for simplicitys sake, only four radial arms l lad which difier from the arms Ila-c in Figs. 2 and 3 by being longitudinally slotted at l5. The arms l la--d, which are turnable about the common axis 01, are equally axially spaced from each other so that the arm l4la is the lowermost, and the arms l lb, Mo and hid are progressively higher. Pivotally-mounted at ,d"

on the arms l4ad remote from their longitu dinal axes .r-a: are the rockers lfla to Hid, respectively, and coaxially pivotally mounted at c on the arms Mb and Ida, respectively, are the link pairs 9a, and 9b, M, respectively, which are pivotally connected at b with the rockers Illa, I00 and ltlb, Hid, respectively. The farther the pivot mountings a of the cooperating rocker pairs lEIa, I00 and llib, llld, respectively, are spaced from each other (by pivotally mounting said rockers at the lateral extremities of their respective arms l4ad) the longer will be the links 912-11 and the sides of said rocker pairs which converge upon their respective floating pivot connections l6, l1 and l6, l1, and the more closely will the pivots l6 and I6 travel in straight paths radially of the pivot 12'. The rocker led is situated in the axial space between the arms Mo and hid, while the rocker lOb, which has the floating pivot connection l6, l! with the former rocker, is situated in the axial space between the arms l lb and M0. The pivot ll; of the connection l6,'l1 extends through, and travels in, the longitudinal slot It in the arm Mc substantially radially of the pivot d". Also situated in the axial space between the arms I la-and Md, though in planes other than that of the rocker llld, are the links 9b and 911, respectively. The rocker lElc is, like the rocker lllb, situated in the axial space between the arms Mb and Mo, but below said rocker lllb so as not to interfere with the floating pivotal connection'lfi, l'l between the latter and the rocker I001. The rocker Illa, which has the floating pivotal connection it, I? with the rocker N30, is situated in the axial space between the arms Ma and Mb. The pin l5 of the connection l6, H extends through, and travels in, the longitudinal slot l5 in the arm ltb substantially radially of the pivot 02''. Also situated in the axial space between the arms Nb and I40, though in planes other than that of the rockers 10b and H10, are the links 9a and 9c, respectively. In thus grouping the various parts of the construction none of these parts will interfere with the movements of the other parts, and the angular extension and contraction of the arms I la-d is solely limited by the possible extent of travel of the pins l6 and It in the longitudinal slots l5 of the arms Me and Mb, respectively. The described grouping of the parts may be repeated for any desired number of arms,- and the angular extension and contraction of the latter is, as in the case of four arms (Fig. 4), solely limited-bythe possible extent of travel of the'pins of the floating pivotal connections in-thelongitudinal slots in the arms. Inasmuch as thelongitudinal axes a::c of the arms l-4ad are also symmetrical axes, and the pivot mountings c", c of thelinks 9a, 90 and 9b, 9d, respectively, 1ie=in t11e symmetrical axes of the arms Mband l lc, respectively, and the pivot mountings a of'the rockers l!!ad are equally spaced from-:thesymmetrical axes ar-a: of their respective arms l4ad, it follows that the arms--Ma-'d are equi- 1angularly spaced in any relative angular disposiion.

In analyzing the construction shown in Fig. 4, each rocker lilo-11 maybe considered a 'link which forms with its respective, connecteds'link 9ad a relatively rotatable link pair. The pairs of relatively rotatable linksconnect the angularly spaced arms, respectively, with the adjacent opposite arms, respectively, whilexthe-floating pivotal connections between the rockersservc as means for guiding the links of the several pairs for relative rotation so that the intended relative turning movements of the arms may take place.

An example of one of many practical applications of the present invention is illustrated in Figs. to 8. The instrument there illustrated is a watch or similar time piece adapted primarily for use in connection with the navigation of aircraft, and is in many respects like the time piece shown and described in said prior application, Serial No. 393,517, filed May 15, 1941. Thus, the dial H; of the time piece (Fig. 5) has a central portion is graduated in the usual manner in hours and minutes and over which are movable the usual hour and minute hands 20 and 2|, respectively, and surrounding and disposed concentric with the portion I9 is an annular time scale 22, likewise graduated in minutes and hours, although preferably on a different basis, and movable over and in cooperation with which is a third hand 23 whose timing, or speed of movement, corresponds to the graduations of said scale 22, and whose operating mechanism includes means whereby it can be returned to zero position, at any time and started from this position at the will of the operator. Also surrounding, and disposed concentric with, the time scale 22, in a position likewise to cooperate with the hand 23, is an arcuate, extensible and contractible, combined distance and speed scale indicated as a whole at it, carrying distance or speed interval indicia elements 23, identified at convenient points by suitable numerals and constituting graduations whose spacing varies with the extension and contraction of the scale as a whole. One end of the scale 24, namely, what may be considered the zero end thereof, is fixed adjacent the zero point of the scale 22,and its opposite end is connected to a bezel or ring (Figs. 7 and 8) rotatably mounted on the watch or clock case 21, whereby rotation of said bezel with respect to said case and the dial I8 will cause circumferential extension or contraction of the scale 24, thereby causing the indicia elements 23 thereof to register with the graduations of the scale 22 in variable relationship. In use, the bezel is turned to cause the index element 25 of the scale 24 corresponding to the assumed or estimated ground speed (e. g., as shown in Fig. 5, 50 miles per hour) to register with the one hour point on the scale 22. The hand 23, being in zero position, is started from said position at the instant of departure. Thereafter, the hand 23 will, at any moment, indicate on the scale 22 the distance traversed from the point of departure at that moment if the initially assumed ground speed for which the instrument has been set is correct. At the time of arrival, however, over a recognizable landmark whose distance from the point of departure is known, the pilot can, if necessary, correct the setting of the instrument by turning the bezel 25 to bring said known distance on the scale 24 into register with the position of the hand 23 at that time, whereupon the actual ground speed will be indicated on the scale 24 opposite the one hour point on the scale 22, and the hand 23 will thereafter, at all times, correctly indicate on the scale 24 the distance covered.

The construction and operation of the instrument as thus far outlined are or may be substantially as more fully described in the prior application above reierred to. The present invention is applied for guiding and controlling the arouate extension and contraction of the scale 24 to the end that such extension and contraction shall be accurately proportionate throughout, the variation of the spacing of the indicia or graduations shall be in constant ratio to theextension and contraction of the scale as a whole and the several indicia be accurately held in substantially fixed, invariable positions for a given setting of the scale 24. I

The dial I 8 is supported by, and in spaced relation to, a base plate 30 carried by the watch or clock case 21 as follows. Secured, as by screws 3| (Fig. 6), to the base plate 30, in a region below a portion of the scale 22 angularly remote from the zero end thereof, is the lower end portion 32 of an angular bracket member having an upwardly inclined portion 33 (see also Fig. '7) supporting a portion 34 disposed parallel to the portion 32, plate 35, and dial l8 in a region below the scale 22 (and scale 24) adjacent the zero end thereof, said bracket portion 34 terminating in an upwardly or outwardly turned end 35. Extending between the base plate 30 and dial I8 is a cen-- tral post 33 formed hollow to receive thenested arbors of the several hands of the timepiece. Extending between the upper or outer end of the post 36 and the upwardly or outwardly turned end 35 of the bracket portion 34, is a bridge member 31 by which the dial I8 is supported and to which it is secured in any suitable manner. Rotatably mounted on the post 36 are the inner ends or hub portions 38 of radial arms l4 (similar to those shown in Fig. 4), said arms being disposed in a superposed series, and their several hub portions being separated by washers or spacers 40, as shown in Fig. '7. The equi-angularly spaced arms Me, Mi, big-Mn (Fig. 6) are interconnected by links 9 and rockers ill in the same manner as the arms in Fig. 4, so that they are relatively rotated in equiangularly spaced relationship when any one of the arms is turned. More particularly, the links 9 and rockers III are situated in the axial spaces between the arms Me, I41, lag-Mn in the manner explained inconnection with Fig. 4, so that the angularextension' and contraction of these arms is solely limited by the possible extent of travel of the pins [6 in-the longitudinal slots l5 of said arms. The first or lowermost rocker Ice in Fig. 6 is rotatably mounted on a fixed pivot a on the base 33 so that all arms l4e-n are turned when any one of said arms is turned. With the arms I4, links v9 and rockers [4 thus coordinated, the arms Me, I4 l4g-l4n are turned in equi-angularly spaced relation if any one of these arms is turned. The outer ends of the-arms M are guided on the outer margin of the base plate 30 by rollers 4| carried by angular extensions 42 at said outer ends which are of suitable lengths, respectively, to bring the axes of the several rollers into the proper common plane.

As in the prior application aforesaid, the scale 24 as herein shown comprises a lazy-tongs structure, being in the present instance composed of a plurality of sections of equal length joined end to end to form the complete structure. The index element 23a at the zero end of the scale is secured to the base plate 30 by a pair of bolts 50 and 5] formed with shoulders 52 (Fig. '7 whereby said element is suitably spaced from said plate. Similarly, each of the arms M has secured thereto, adjacent its outer end and at the same spacing from the base plate 30 as the index element 26a, an index element 26b, 26c, 26d, 26e26n by means of shouldered bolts 50b5I]e-5Un and 5lb-5le5ln. The bolt em for securing the index e ement 26 1 to the arm n a the free end i th lazy-ton s st uctu i. a, t e end opposite the zero end thereof, has an extension53 (Fig. 8) received in a socket 54 formed in the inner face of the bezel 25. The end link 55d (Fig. 6) at the zero end of the lazy-tongs section 24b at the zero end of the scale 24 is pivoted on the end of the bolt The link 551i at the other end of the lazy tongs structure is pivoted on the end of the bolt em. The links 55 at the contiguous ends of adjacent or successive sections of the structure have common pivotal connection to the respective arms M by means of the bolts 51b, 5Ic, etc.

The angularly movable arms [4, connected as just described with the lazy-tongs structure at the points of junction of the equal sections thereof, and therefore connected with the structure as a whole at equally spaced points circumferentially thereof, serve to guide the arcuate expension and contraction of said structure or scale, and since the angular approach and separation of adjacent arms is in constant ratio throughout the series of arms, the equal expansion of the scale throughout its length will be preserved.

I claim:

1. Mechanism comprising more than two angularly spaced, relatively coaxially turnable arms; and a device relatively turning said arms equal angular amounts on turning one arm, said device comprising pairs of relatively turnable links connecting said arms, respectively, with the adjacent opposite arms, respectively, and means guiding the links of each pair for relative turning movement.

2. Mechanism as set forth in claim 1, in which the link pairs are identical and their corresponding pivot connections, respectively, with the arms are equidistant from the turning axis of said arms.

3. Mechanism as set forth in claim 1, in which said link guiding means are carried by some of said links.

4. Mechanism comprising more than two angularly spaced, relatively coaxially turnable arms; and a device relatively turning said arms equal angular amounts on turning one arm, said device comprising identical pairs of relatively turnable links connecting said arms, respectively, with the adjacent opposite arms, respectively, the corresponding pivot connections, respectively, of said link pai s w t the a ms b in quidi a fr m the turn n axis o t e latt and me n equiansu ar y spac h lin o each pai said means also equally varying the angle between the links of each pair on turning one arm relative to the other arms.

5. Mechanism comprising more than two an.- gularly spaced, relatively coaxially turnable arms; and a device relatively turning said arms equal angular amounts on turning one arm, said device comprising pairs of relatively turnable links connecting said arms, respectively, with the adjacent opposite arms, respectively, and connections between opposite links of said pairs, respectively, said arms, links and connections being so coordinated that the latter move in paths approximately radial of the turning axis of said arms on relative turning movement of the latter.

6. Mechanism as set forth in claim 5, in which said connections are pivotal connections fioatable transversely to said radial paths.

7. Mechanism comprising at least three angularly spaced arms relatively turnable about a common axis; two rockers pivotally mounted on the outer arms, respectively, at an equi-distance from said common axis; two links, each of a length equal to said equi-distance, connecting said rockers, respectively, with a common point on the intermediate arm; and a floating pivotal connection between said rockers including a pin on one rocker spaced at said equi-distance from the pivot mounting of said one rocker and the turning point thereon of the link connected therewith.

8. Mechanism as set forth in claim 7, in which said floating pivotal connection further includes a slot in the other rocker receiving said pin and extending transversely to a direction radially of said common axis.

9. Mechanism as set forth in claim 7, in which the outer arms have lateral outward extensions on which the rockers, respectively, are pivotally mounted remote from the longitudinal axes of said arms.

10. Mechanism as set forth in claim '7, in which said arms are axially spaced and said rockers interposed in the axial spaces, respectively, between said arms, and said intermediate arm has a longitudinal slot through which said pin extends.

JOHN P. PU'INAM. 

